Ask YC: Anyone working on applications for Craigslist?

Today I stumbled upon a great program that makes reading craigslist easier. It's called Craigslist Reader and is available here:

http://www.motiont.com/

(My review is here: http://breckyunits.com/?p=52)

A lot of Web 2.0 apps piggyback on the big sites to achieve success (Auctomattic, Facebook apps, etc.). I think this is a terrific strategy because these sites have millions of daily users who have many unmet wants. I was wondering if anyone here has been working on (or know of any) apps that would benefit craigslist users.

I'm not planning on developing any, actually I'm just curious because I use craigslist a fair amount.